Conventionally known vehicle lights, in particular, vehicle headlights can form a desired light distribution pattern by superposing, on a basic light distribution pattern, at least one additional light distribution pattern using at least two reflecting surfaces (see, for example, Japanese Patent Application Laid-Open No. 2003-317513). An exemplary vehicle headlight of this type can have an LED light source, a first reflecting surface for reflecting light from the LED light source to form a basic light distribution pattern, and a second reflecting surface for reflecting a part of light reflected from the first reflecting surface to form an additional light distribution pattern.
A united component for use in a conventional vehicle headlight is shown in FIG. 1. Hereinafter, the united component shall be referred to as a “vehicle lighting unit,” a “vehicle headlight unit” or simply a “unit.” The unit 1000 includes a projection lens 100, an LED light source 120 having an optical axis, a first reflecting surface 130 disposed along the optical axis of the light source in front of the LED light source 120 so as to cover the LED light source 120, a shade 140 horizontally disposed between the projection lens 100 and the LED light source 120, a second reflecting surface 150 formed on or above the upper surface of the shade 140, and the like.
In the vehicle headlight unit 1000 of FIG. 1, light emitted from the LED light source 120 is totally reflected by the first reflecting surface 130. Part of the reflected light is allowed to directly pass through the projection lens 100 to form the basic light distribution pattern. Another part of the reflected light is allowed to be reflected by the second reflecting surface 150 and pass through the projection lens 100 to form the additional light distribution pattern to be superposed on the basic light distribution pattern.
In general, a light distribution pattern formed by a vehicle headlight is configured to include a region provided with the highest intensity of light in the vicinity of a light/dark border closer to pedestrians and another region provided with a relatively low intensity of light closer to an opposed vehicle in view of the reflection from a wetted road surface.